Description: This function creates elements of specific type by connecting selected nodes or points. The element type refers to the analysis program defined at the creation of the database. Depending on the analysis program, NASTRAN or LS-DYNA, DSI offers a list of element types and prompts the user to select one. Because the NASTRAN element types are more comprehensive, they are documented first in the following pages with the LS-DYNA elements following.
Description: This section covers the options for the BEAM ELEMENT subsection of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> ENTER CBAR OFFSET VALUE
2. Once offset value has been entered, the prompt will read:
> PICK NODES/POINTS FOR CBAR ELEMENT
• To create the elements, the user may select a node, point, keyboard entry, or any combination of the three.
3. Once the desired nodes/points have been selected, DSI prompts:
> PICK NODE/PT OR VECTOR FOR CBAR ORIENTATION
• Up to three values may be entered to define a vector in the bar¡¯s local XY plane. The local Y-axis of the bar will be plotted at the first node of the bar element as it is generated.
4. If user enters VECTOR, then DSI prompts:
> ENTER CBAR VECTOR
• i.e., 0,0,1
Description: This section covers the options for the RIGID LINK subsection of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> ENTER DEPENDENT D.O.F. (DEFAULT 123456 OR ¨C1 TO EXIT)
• Any combination of integers 1, 2, 3, 4, 5 and 6 may be entered as degrees of freedom.
• Blanks or commas are not allowed between the degrees of freedom. i.e., 123456 = all D.O.F.
2. Next, DSI prompts for nodes/points for element:
> PICK NODES/POINTS
> AT INDEPENDENT NODE
• To create the elements, the user may select a node, point, keyboard entry, or any combination of the three.
3. Once the desired node or point has been selected, DSI prompts:
> AT DEPENDENT NODE
• The user may select up to 200 dependent nodes.
4. Once the user picks the dependent node(s), DONE registers the selection and restarts the prompt cycle.
Description: This section covers the options for the PLOTEL ELEMENT subsection of CREATE ELEMENTS. PLOTEL elements are used as the cross-section pattern for the DRAG MESH operation.
Usage:
1. DSI prompts:
> PICK NODES/POINTS FOR ELEMENT
• To create the elements, the user may select a node, point, keyboard entry, or any combination of the three.
• An element will be created after two nodes/points are selected.
• EXIT or ABORT will exit this function.
Note: PLOTEL elements may be output to a NASTRAN bulk data file. They are ignored for other analysis programs.
Description: This section covers the options for the PLATE ELEMENT (quadrilateral and triangular) subsection of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> PICK NODES/POINTS FOR ELEMENT
• To create the elements, the user may select a node, point, keyboard entry, or any combination of the three.
• A CQUAD4 ELEMENT requires 4 nodes or points to be selected.
• A CTRIA3 requires 3 nodes or points to be selected, then an entry of DONE.
• EXIT or ABORT will exit this function.
Description: This section covers the options for the SOLID ELEMENT (cube, wedge, tetrahedron) subsection of CREATE ELEMENTS.
Usage:
Note: A solid element cannot be created in a part that has plate properties. The user must either create a new part and assign it solid properties or make a part current that contains solid properties.
1. DSI prompts:
> PICK NODES/POINTS FOR SOLID ELEMENT
• To create the elements, the user may select a node, point, keyboard entry, or any combination of the three:
CTETRA: Pick 4 nodes/points and type DONE.
CPENTA: Pick 6 nodes/points (pick the second set of 3 nodes/points in the same order as the first set of 3 nodes/points) and type DONE.
CHEXA: Pick 8 nodes/points (pick the second set of 4 nodes/points in the same order as the first set of 4 nodes/points). The element will be created.
• EXIT or ABORT terminates this function.
Description: This section covers the options for the SPRING ELEMENT (NASTRAN CELAS2) sub-section of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> ENTER SPRING DIRECTION (1 to 6) AT EACH END
• Two entries are required, one for each end of the spring (e.g., 1,1) for the "x" direction.
• Any number of spring elements may be created for the same connectivity depending upon the number of directions required.
1 - translational along the global X-axis
2 - translational along the global Y-axis
3 - translational along the global Z-axis
4 - rotational along the global X-axis
5 - rotational along the global Y-axis
6 - rotational along the global Z-axis
2. Once the desired direction has been entered for the spring, DSI prompts:
> ENTER SPRING RATE
• Any positive real number may be entered for the spring rate.
3. DSI prompts:
> PICK NODES/POINTS FOR ELEMENT
• To create the elements, the user may select a node, point, keyboard entry, or any combination of the three.
• Select 2 nodes/points. The element will be created.
• EXIT or ABORT terminates this function.
Description: This section covers the options for the general SPRING ELEMENT subsection of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> ENTER SPRING DIRECTION (1 to 6) AT EACH END
• Two entries are required, one for each end of the spring (e.g., 1,1) for the "x" direction.
• Any number of spring elements may be created for the same connectivity depending upon the number of directions required.
1 - translational along the global X-axis
2 - translational along the global Y-axis
3 - translational along the global Z-axis
4 - rotational along the global X-axis
5 - rotational along the global Y-axis
6 - rotational along the global Z-axis
• Once the desired direction has been entered for the spring, DSI prompts the user to enter a property. If no properties exist in the database at the current time DSI prompts to create one.
2. DSI prompts:
> PICK NODES/POINTS FOR CELAS1 ELEMENT
• To create the elements, the user may select a node, point, keyboard entry, or any combination of the three.
• Select 2 nodes/points. The element will be created.
• EXIT or ABORT will exit this function.
Description: This section covers the options for the RIGID BAR section of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> ENTER D.O.F. (CNA, CNB, CMA, CMB)
• Any combination of integers 1, 2, 3, 4, 5 and 6 may be entered as degrees of freedom.
1 - translational along the global X-axis
2 - translational along the global Y-axis
3 - translational along the global Z-axis
4 - rotational along the global X-axis
5 - rotational along the global Y-axis
6 - rotational along the global Z-axis
• Blanks or commas are not allowed between the degrees of freedom, i.e. 123,456,456,345
2. Once the desired D.O.F. has been entered the prompt will read:
> PICK NODES/POINTS FOR ELEMENT
• To create the elements, the user may select a node, point, keyboard entry, or any combination of the three.
• Once the desired nodes (2) or points (2) have been selected, the element will be created.
• EXIT or ABORT will exit this function.
Description: This subsection covers the options for the MASS subsection of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> DEFINE CONM2 ELEMENT COORDINATE SYSTEM
2. DSI prompts:
> ENTER MASS VALUE AND MOMENTS OF INERTIA
• DSI displays a pop up window with the following items: I11, I21, I22, I31, I32, I33 etc. = MOMENT OF INERTIA
• The user may enter only the mass if desired. The moment of inertia is an optional entry.
• The user should remember that the units of the CONM2's should be consistent with the units of the database, e.g., DATABASE (MM.) = CONM2 (KG.)
3. DSI prompts:
> PICK NODES/POINTS FOR ELEMENT
• To create the elements, the user may select a node, point, keyboard entry, or any combination of the three.
• The elements will be created simultaneously upon selection of the desired nodes/points.
• EXIT or ABORT will exit this function.
Description: This subsection covers the options for the BEAM (NASTRAN CBEAM) section of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> ENTER CBEAM OFFSET VALUE
• DSI displays a pop up window of CBEAM OFFSET VALUE
2. Once the beam offset value has been entered the prompt will read:
> PICK NODES/POINTS FOR CBEAM ELEMENT
• To create the elements, the user may select a node, point, keyboard entry, or any combination of the three.
3. Once the desired nodes/points have been selected, DSI prompts:
> PICK NODE/PT OR VECTOR FOR CBEAM ORIENTATION
• Up to three values may be entered to define a vector normal to the beam¡¯s local XY plane.
4. When user enters VECTOR, DSI prompts:
> ENTER CBEAM VECTOR
• i.e., 0,0,1
Description: This section covers the options for the TRUSS ELEMENT subsection of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> ENTER NEW PROPERTY NAME OR "EX" TO EXIT
• DSI prompts the user to enter a property name if no properties exist in the database at the current time. Once a name is entered, a pop-up window will appear with a list of properties to edit.
2. Once the property ID has been entered the prompt will read:
> PICK NODES/POINTS FOR ELEMENT
• To create the elements, the user may select a node, point, keyboard entry, or any combination of the three.
• An element will be created after two nodes/points are selected.
• EXIT or ABORT will exit this function.
Description: This section covers the options for the HOLLOW TUBE subsection of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> ENTER NEW PROPERTY NAME OR "EX" TO EXIT
• DSI prompts the user to enter a property name if no properties exist in the database at the current time. Once a name is entered, a pop-up window will appear with a list of properties to edit.
2. Once the property ID has been entered the prompt will read:
> PICK NODES/POINTS FOR ELEMENT
• To create the elements, the user may select a node, point, keyboard entry, or any combination of the three.
• An element will be created after two nodes/points are selected.
• EXIT or ABORT will exit this function.
Description: This section covers the options for the ISOPARAMETRIC SHELL subsection of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> PICK NODES/POINTS FOR ELEMENT
• Generating isoparametric tri or quad elements require the user to select three nodes/points per side (6).
Description: This section covers the options for the RIGID BODY (RBE3) subsection of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> ENTER COMPONENT NUMBERS (DEFAULT 123456 OR ¨C1 TO EXIT)
• Defines the degrees of freedom.
2. DSI prompts:
> SELECT REFERENCE NODE FOR RBE3
3. DSI prompts:
> ENTER WEIGHTING FACTOR WT 1 (REAL) OR "0" TO END
> ENTER COMPONENT WITH WEIGHTING FACTOR (DEFAULT 123)
> FOR NODE WITH WEIGHTING FACTOR .100E+01
> SELECT INDEPENDENT NODES
4. Step 3 is repeated until the user selects DONE or ABORT.
Description: This function allows the user to create local coordinate systems to be attached to the RBAR or RBE2 elements for the application of weld study. Two options are provided. The first option creates the RBAR and attaches the local coordinate systems at each node automatically. The second option attaches the local coordinate system automatically to the existing RBAR elements.
Usage:
1. DSI prompts:
> SELECT COORDINATE SYSTEM TYPE
2. DSI prompts:
> SELECT LOCAL AXIS ALONG RBAR/RBE2
3. DSI prompts:
> SELECT OPTION TO CREATE SPOTWELD
4. DSI prompts:
> SELECT NODE/POINT FOR INDEPENDENT NODE
• This step is repeated once, and the SPOTWELD is defined.
• Once the SPOTWELD is defined, its coordinate system is displayed.
Description: This function defines a NODAL RIGID BODY element between multiple nodes. The first selected node serves as a reference point; all additional nodes are connected to this first node (usually the center of the rigid body) for display purposes.
Usage:
1. DSI prompts:
> SELECT THE FIRST NODE FOR RIGID BODY
• The first node is selected.
• Nodes can be selected by cursor pick, drag window, multi-point region, or part.
> SELECT NODES
• The second and subsequent nodes are selected until the user selects DONE.
• The rigid body is displayed with double lines with an "R" alongside it.
Description: This section covers the options for the THICK SHELL subsection of CREATE ELEMENTS.
Note: A solid element cannot be created in a part that has plate properties. The user must either create a new part and assign it solid properties or make a part current that contains solid properties.
Usage:
1. DSI prompts:
> PICK NODES/POINTS FOR ELEMENT
• To create the elements, the user may select a node, point, keyboard entry, or any combination of the three:
• EXIT or ABORT terminates this function.
Description: This function defines a spring/damper element between two nodes/points. It is recommended that the user select the ATTRIBUTE TABLE ON/OFF in the element options menu prior to creating a spring/damper. This will pop-up the ELEMENT DISCRETE CARD for user input.
Usage:
1. DSI prompts:
> PICK NODES/POINTS FOR ELEMENT
• This step is repeated once.
• When the second node/point is defined, DSI displays the SPRING/DAMPER element.
Description: This function defines a seatbelt element between two nodes/points. Other seatbelt functions such as ACCELEROMETER, RETRACTOR, SENSOR, etc. are located in the DYNA MISCELLANEOUS menu.
Usage:
1. DSI prompts:
> PICK NODES/POINTS FOR ELEMENT
• This step is repeated once.
• When the second node/point is defined, DSI displays the SEATBELT element.
2. Once the seatbelt elements have been created it is recommended that the user enter the DYNA MISC. menu in the PRE PROCESSOR menu and select SEATBELT to define the accelerometer, pretensioner, retractor, sensor, and slipring.
Description: This function allows the user to create joints for DYNA analysis. All types of joints are supported. The procedure to create joints has been simplified to create the coincident nodes for the second rigid body. The program first prompts for the Relative Penalty Stiffness (default=1.0). The program next prompts the user to select the first part (rigid body with material type 20) for the joint. If no material is defined for the selected part, the program prompts a warning message: "NO MATERIAL ASSIGNED TO SELECTED PART". The program then prompts the user to select necessary nodes in the first rigid body to define the orientation of the joint. The requirements for each type of joint are listed in the following table:
JOINT TYPE |
NUMBER OF NODES |
ORIENTATION |
IDENTIFIER SYMBOL |
Spherical |
1 (N1) |
Center |
SJ |
Revolute |
2 (N1,N3) |
Axis of Rotation |
RJ |
Cylindrical |
2 (N1,N3) |
Axis of Cylinder |
CJ |
Planar |
2 (N1,N2) |
Normal of Plane |
PJ |
Universal |
3 (N1,N3,N4) |
Center, End Points of the Perpendicular Axes |
UJ |
Translational |
3 (N1,N3,N5) |
Direction & Plane of Translation |
TJ |
Locking |
3 (N1,N3,N5) |
Axis & Plane |
LJ |
The program then prompts the user to select the second part (rigid body with material type 20) for the joint. All the required coincident nodes on the second part will be created and added to the second rigid body as CONSTRAINED_EXTRA_NODES_NODES. The following will take create locking as example:
Usage:
1. DSI prompts:
> SELECT JOINT TYPE
2. DSI prompts:
> ENTER RELATIVE PENALTY STIFFNESS (1.0)
3. DSI prompts:
> SELECT 1ST PART (RIGID BODY ONLY) FOR JOINT
> PICK AN ELEMENT OR PART NAME OF A PART
4. After part is selected, DSI prompts:
> PICK NODE ON RIGID BODY FOR THE JOINT
5. DSI prompts:
> PICK 2ND NODE ON RIGID BODY TO DEFINE THE 1ST AXIS OF JOINT
6. DSI prompts:
> PICK 3RD NODE ON RIGID BODY TO DEFINE THE PLANE OF THE JOINT
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Description: This section covers the options for the PLOTEL ELEMENT subsection of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> PICK NODES/POINTS FOR ELEMENT
• This step is repeated until user enters ABORT or EXIT.
Description: This section covers the options for the INERTIA subsection of CREATE ELEMENTS.
Usage:
1. DSI prompts to define local coordinates
2. After local coordinates are defined, DSI prompts:
> ENTER MASS INERTIA: Ixx, Ixy, Ixz, Iyy, Iyz & Izz
3. DSI prompts:
> PICK NODES/POINTS FOR ELEMENT
Description: This section covers the options for the CONST. NODE SET subsection of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> ENTER APPLICABLE DOF: 1 TO 7, TYPE 0 TO EXIT
2. DSI prompts:
> SELECT THE FIRST NODE FOR CONST. NODE SET
3. DSI prompts:
> SELECT NODES
Description: This section covers the options for the CONST. INTERPOLATION subsection of CREATE ELEMENTS.
Usage:
1. DSI prompts:
> ENTER COMPONENT NUMBERS (DEFAULT 123456 OR ¨C1 TO
EXIT)
• Defines the degrees of freedom.
2. DSI prompts:
> SELECT REFERENCE NODE FOR CONST. INTERPOLATION
3. DSI prompts:
> ENTER COMPONENT WITH WEIGHTING FACTOR (DEFAULT
123456)
> ENTER WEIGHTING FACTOR WT 1 (REAL) OR "0" TO END
> SELECT INDEPENDENT NODES FOR CONST. INTERPOLATION
4. Step 3 is repeated until the user selects DONE or ABORT.
Description: This section covers the options for the ALDS subsection of CREATE ELEMENTS.
Usage: this function will create ALDS(Arbitrary Location Deformable Spotweld) elements,
1. After define the section beam, DSI prompts:
> SELECT MASTER PART
> SELECT AN ELEMENT OR PART NAME OF A PART.
2. After select a part, DSI prompts:
> SELECT PART 2
> SELECT AN ELEMENT OR PART NAME OF A PART.
• User can select the third part here
3. After click EXIT, DSI prompts:
> PICK ALDS LOCATION
• Click cursor on the screen, ALDS is created. The contact between ALDS and elements they connect are created automatically.
Description: This section covers the options for the MAT100 SPOTWELD subsection of CREATE ELEMENTS.
Usage: this function will create MAT100 Spotweld elements,
1. After define the section beam and mat100 card, DSI prompts:
> SELECT MASTER PART
> SELECT AN ELEMENT OR PART NAME OF A PART.
2. After select a part, DSI prompts:
> SELECT PART 2
> SELECT AN ELEMENT OR PART NAME OF A PART.
• User can select the third part here
3. After click EXIT, DSI prompts:
> PICK MAT 100 SPOTWELD LOCATION
• Click cursor on the screen, MAT100 spotweld is created. The contact between ALDS and elements they connect are created automatically.